RESUMO
A chromatography-free, asymmetric synthesis of the C2-symmetric P-chiral diphosphine t-Bu-SMS-Phos was developed using a chiral auxiliary-based approach in five steps from the chiral auxiliary in 36% overall yield. Separtion and recovery of the auxiliary were achieved with good yield (97%) to enable recycling of the chiral auxiliary. An air-stable crystalline form of the final ligand was identified to enable isolation of the final ligand by crystallization to avoid chromatography. This synthetic route was applied to prepare up to 4 kg of the final ligand. The utility of this material was demonstrated in the asymmetric hydrogenation of trifluoromethyl vinyl acetate at 0.1 mol % Rh loading to access a surrogate for the pharmaceutically relavent chiral trifluoroisopropanol fragment in excellent yield and enantiomeric excess (98.6%).
RESUMO
An efficient asymmetric synthesis of 11-ß-HSD inhibitor 1 has been accomplished in five linear steps and 53% overall yield, starting from the readily available 3-chloro-1-phenylpropan-1-one. The key feature of the synthesis includes an asymmetric methallylation of 3-chloro-1-phenylpropan-1-one catalyzed by the highly effective organocatalyst (S)-3,3'-F2-BINOL under solvent-free and metal-free conditions.
Assuntos
11-beta-Hidroxiesteroide Desidrogenases/antagonistas & inibidores , Naftóis/síntese química , Propano/análogos & derivados , 11-beta-Hidroxiesteroide Desidrogenases/química , Catálise , Cetonas/química , Naftóis/química , Propano/síntese química , Propano/química , EstereoisomerismoRESUMO
A practical sequence involving a noncryogenic stereospecific boronate rearrangement followed by a robust formylation with an in situ generated DCM anion has been developed for the asymmetric construction of an all-carbon quaternary stereogenic center of a FLAP inhibitor. The key boronate rearrangement was rendered noncryogenic and robust by using LDA as the base and instituting an in situ trapping of the unstable lithiated benzylic carbamate with the boronic ester. A similar strategy was implemented for the DCM formylation reaction. It was found that the 1,2-boronate rearrangement for the formylation reaction could be temperature-controlled, thus preventing overaddition of the DCM anion and rendering the process reproducible. The robust stereospecific boronate rearrangement and formylation were utilized for the practical asymmetric synthesis of a chiral quaternary FLAP inhibitor.
Assuntos
Inibidores da Proteína Ativadora de 5-Lipoxigenase/síntese química , Compostos de Boro/química , Carbamatos/química , Inibidores da Proteína Ativadora de 5-Lipoxigenase/química , Catálise , Estrutura Molecular , EstereoisomerismoRESUMO
2-[4-(3-{(1R)-1-[4-(2-Aminopyrimidin-5-yl)phenyl]-1-cyclopropylethyl}-1,2,4-oxadiazol-5-yl)-1H-pyrazol-1-yl]-N,N-dimethylacetamide (1), is a novel and selective five-lipoxygenase activity protein (FLAP) inhibitor with excellent pharmacokinetics properties. The availability of a key chiral intermediate allowed the synthesis of [(14) C]-(1) in six radiochemical steps and in 47% overall radiochemical yield with a specific activity of 51 mCi/mmol using carbon-14 zinc cyanide. 2-Chloro-N,N-dimethyl-(2)H6-acetamide was prepared and condensed with a penultimate intermediate to give [(2)H6]-(1) in very high yield and in more than 99% isotopic enrichment.
Assuntos
Radioisótopos de Carbono/química , Deutério/química , Marcação por Isótopo/métodos , Inibidores de Lipoxigenase/química , Compostos Radiofarmacêuticos/síntese química , Inibidores de Lipoxigenase/isolamento & purificação , Compostos Radiofarmacêuticos/isolamento & purificaçãoRESUMO
A practical and efficient synthesis of a complex chiral atropisomeric HIV integrase inhibitor has been accomplished. The combination of a copper-catalyzed acylation along with the implementation of the BI-DIME ligands for a ligand-controlled Suzuki cross-coupling and an unprecedented bis(trifluoromethane)sulfonamide-catalyzed tert-butylation renders the synthesis of this complex molecule robust, safe, and economical. Furthermore, the overall synthesis was conducted in an asymmetric and diastereoselective fashion with respect to the imbedded atropisomer.
Assuntos
Inibidores de Integrase de HIV/síntese química , Integrase de HIV/química , HIV/enzimologia , Acilação , Catálise , Cobre/química , Integrase de HIV/metabolismo , Inibidores de Integrase de HIV/química , Humanos , Ligantes , Estereoisomerismo , Sulfonamidas/químicaRESUMO
An enantioselective copper-catalyzed asymmetric conjugate addition of Me2Zn to (Z)-nitroalkenes led to the formation of all-carbon quaternary stereogenic centers with high stereoselectivity. The key features of the new method are the unprecedented use of [(MeCN)4Cu]PF6 in conjunction with the Hoveyda ligand L1 and the use of (Z)-nitroalkene substrates so that undesired nitroalkene isomerization is minimized and enantioselectivity is enhanced dramatically. We also describe a novel, practical, and highly (Z)-selective nitroalkene synthesis.
Assuntos
Alcenos/química , Cobre/química , Nitrogênio/química , Compostos Organometálicos/química , Catálise , Cromatografia Líquida de Alta Pressão , Isomerismo , Ligantes , EstereoisomerismoRESUMO
An operationally simple copper-BINAP-catalyzed, highly enantioselective propargylation of ketones is presented. The methodology was developed as an enantioselective process for methyl ethyl ketone and shown to be applicable to a wide variety of prochiral ketones. The resulting homopropargyl adducts are versatile latent carbonyls from which γ-butyrolactones, ß-hydroxy methyl ketones, and ß-hydroxycarboxylates are readily obtained.
Assuntos
Ácidos Borônicos/química , Butanonas/química , Cobre/química , Cetonas/química , Naftalenos/química , Catálise , Pargilina/químicaRESUMO
A one-pot process has been developed for the synthesis of 8-arylquinolines via Pd-catalyzed borylation of quinoline-8-yl halides and subsequent Suzuki-Miyaura coupling with aryl halides using n-BuPAd(2) as ligand. Yields of up to 98% were obtained.
Assuntos
Hidrocarbonetos Halogenados/química , Paládio/química , Quinolinas/síntese química , Catálise , Ligantes , Estrutura Molecular , Quinolinas/químicaRESUMO
A practical noncryogenic process for the Aggarwal stereospecific boronate rearrangement with chiral secondary benzylic carbamates has been developed. The use of LDA instead of sec-BuLi combined with an in situ trapping of the unstable lithiated carbamate was critical to success. Furthermore, this new process increased the substrate scope to include the versatile aryl iodide and bromide substrates. The methodology was applied to a diverse array of substrates and was demonstrated on multikilogram scale.
Assuntos
Compostos de Benzil/química , Ácidos Borônicos/síntese química , Carbamatos/química , Ácidos Borônicos/química , Ésteres , Estrutura Molecular , EstereoisomerismoRESUMO
(S)-3,3'-F2-BINOL has been synthesized for the first time and demonstrated as a highly active organocatalyst for asymmetric methallylation of ketones. Up to 98:2 enantioselectivity and 99% yield were obtained with 5 mol % catalyst loading. The catalyst (S)-3,3'-F2-BINOL could be easily recovered and reused.
Assuntos
Cetonas/química , Naftóis/química , Catálise , Estrutura Molecular , EstereoisomerismoRESUMO
A series of novel P-chiral monophosphorus ligands exhibit efficiency in asymmetric Suzuki-Miyaura coupling reactions, enabling the construction of an array of chiral biaryl products in high yields and excellent enantioselectivities (up to 96% ee) under mild conditions. The carbonyl-benzooxazolidinone moiety in these chiral biaryl products allows facile derivatization for further synthetic applications. A computational study has revealed that a π-π interaction between the two coupling partners can enhance the enantioselectivity of the coupling reaction.
Assuntos
Benzoxazóis/química , Compostos Organofosforados/química , Paládio/química , Catálise , Técnicas de Química Combinatória , Ligantes , Estrutura Molecular , Compostos Organofosforados/síntese química , EstereoisomerismoRESUMO
A general and efficient zinc-alkoxide-catalyzed allylation of a diverse array of ketones with allyl boronates is presented. The methodology is effective with 2 mol % of catalyst and with relatively short reaction times. Studies of the key exchange process are presented, which support a cyclic transition state for the boron to zinc exchange.